Interlocking concrete blocks for pipeline protection

Abstract

Uneven forces, which act mainly in the direction of pipe deviation or movement, are present at the branching and bending parts of underground pressure pipes. To address this issue, concrete is poured on-site around the affected area to cover it, but this requires curing until the concrete develops its strength, and backfilling is not possible, which lengthens construction time, leading to prolonged traffic disruptions and increased construction costs. We are devising a feasible method to replace this method, which significantly shortens construction time. [Solution] When constructing branching and bending sections, terminal sections, and joints of underground pressure pipelines, secondary concrete products are used in the form of blocks, which are connected with PC steel rods and tightly adhered together by applying appropriate tension using a center hole jack, etc. In cases where the structure is small, bolts and nuts are used instead of PC steel rods and fastened with the appropriate torque. In addition, at branching sections, the parts covering the branch pipes are modularized to reduce product costs.

Description

[Technical Field]

[0001] This invention relates to concrete protection applied mainly to the branching and jointing of pressure pipes buried underground. For example, concrete is poured on-site at locations where uneven stress occurs, such as branching, jointing, terminals, or bends of underground pipelines, to make the branching and jointing sections into an integrated structure. This is done to prevent the pipeline from deviating due to uneven stress. [Background technology]

[0002] Examples of prior art related to the protection of pipelines include Showa 55-73076 (Patent Document 1), Japanese Patent Application No. 2003-433515 (Patent Document 2), and Japanese Patent Application No. 2020-206911 (Patent Document 3). Patent Document 1 describes the protection of pipe bodies using a double structure, Patent Document 2 describes an efficient method of protecting the joints of movable pipes using concrete, and Patent Document 3 describes an efficient method for updating underground pipelines. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Document 1: 1980-73076 Patent Document 2: Patent Application No. 2003-433515 Patent Document 3: Patent Application No. 2020-206911 Summary of the Invention [Problem to be solved by the invention]

[0004] It is widely known that uneven forces occur at branching points, joints with different diameters, terminals, and bends in pressure pipes, which can cause the pipes to separate or the pipe itself to move. For this reason, conventional methods include integrating surrounding pipes or pouring concrete on-site at branching points, joints, terminals, and bends to prevent pipe separation or movement. When using the latter method for underground pipes, the concrete must be cured after pouring until it reaches the required strength, necessitating the protection of the surrounding excavation area, including the pouring area, with lining or other protective measures. This is not a problem when the construction project itself is large-scale and the concrete protection area is only a small part of the construction area. However, when the construction project is limited to branching points, bends, terminals, and joints, the construction area is small and the scale of the project itself is small, so providing protection such as linings is extremely expensive. Furthermore, backfilling is not possible until the concrete reaches the required strength, which leads to a longer construction period, increasing construction costs and affecting surface traffic. [Means for solving the problem]

[0005] To solve the above problems, concrete blocks are used for construction of underground pressure pipeline branches, bends, terminals, joints, etc., and these are connected with PC steel rods and tightly adhered by applying appropriate tension with center hole jacks, etc. When the structure is small, bolts and nuts can be used instead of PC steel rods and fastened with the appropriate torque. [Effects of the Invention]

[0006] By using factory-produced secondary concrete products, backfilling is possible immediately after installation, which reduces temporary costs such as lining and shortens construction time.In addition, the quality of the concrete is improved, which improves the strength of the constructed area and makes it more uniform, which can be expected to extend the design life. [Brief explanation of the drawings]

[0007] [Figure 1] Examples of protection at T-junctions [Figure 2] Examples of bent pipe protection [Figure 3] Example of O-shaped pipe protection [Figure 4] Example of protection for hidden crossing pipes [Figure 5] Example of modular structure for T-junction DETAILED DESCRIPTION OF THE INVENTION

[0008] The secondary concrete product is shaped as a multiple-block structure that covers the pipe section to be protected, with holes drilled in each block to allow the passage of PC steel rods and bolts. After installation, the blocks are joined together using PC steel rods, bolts, nuts, etc. to form a single unit. The basic structure is two to four blocks (Figs. 1-4), which sandwich the pipe from the left and right, but for branch sections with a diameter that can suppress uneven stress structurally, the section protecting the branched pipe and the section protecting the branching pipe are separated, creating a modular structure that reduces manufacturing costs (Fig. 5). Also, if there are exposed bolts, gate valves, etc. in the pipe, the space for these is left out and a separate quick-drying resin adhesive or similar is injected to address the issue. [Example]

[0009] As an example, the entire process is similar from pavement breaking to excavation and pipe installation. After that, concrete blocks are lowered into the excavated hole using a small crane, temporarily joined, and any slight misalignment between the blocks is corrected. Once the blocks are positioned, they are fastened using prestressed concrete rods or bolts and nuts through the holes corresponding to the crossings. Important points to note include the need to use crusher run or soil cement appropriately for the basement work depending on the groundwater conditions in the trench, and the need to excavate the area where the center-hole jack can be inserted somewhat wider. Furthermore, for long protection sections, such as those in the ditch, the blocks are divided in the direction of the pipe installation, the joints are joined like joints, and the blocks are fastened together with prestressed concrete rods (Figure 4). Once each block is joined, waterproof caps made of rubber or other materials are attached to the prestressed concrete rod insertion holes to prevent the intrusion of unwanted rainwater and groundwater. [Industrial Applicability]

[0010] While this invention primarily focuses on solving problems associated with cast-in-place concrete, it also allows for the removal of the installed pipe simply by releasing the block structure. This can contribute significantly to the efficiency of future removal work and recycling, such as the efficient sorting of industrial waste. This also contributes to the realization of a sustainable society, which has been a global goal in recent years. Furthermore, by having businesses constantly stock concrete products, PC steel rods, and necessary tools, it is expected that pipeline restoration work after natural disasters will be significantly accelerated, making this invention highly applicable from a disaster response perspective. [Explanation of symbols]

[0011] 101 Pipe 103 PC steel bar 105 Watertight Cap 107 Adhesive injection hole 201 Concrete Block A 203 Concrete Block B 205 Concrete Block C 207 Concrete Block D 209 Concrete Block E

Claims

1. A method of joining secondary concrete blocks with PC steel rods, bolts and nuts, etc., as an alternative to the cast-in-place concrete method used for pipeline branching sections, ends, bends, and irregular joints, etc., and a group of products used for this method.

2. 2. A product according to claim 1, wherein the branch pipe protection portion of the branching section has a modular structure, and the structure of the branched pipe is the same regardless of the diameter of the branch pipe.

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